The present invention relates to a facsimile apparatus or the like using an information source coding system, for example, and having printing means and, more particularly, to a method of controlling the movement of a paper at a printing velocity different in accordance with the content of image signals.
In an apparatus such as a Prior Art facsimile as is disclosed in Japanese Patent Laid-Open No. 58-1579, the printing velocity can be increased by simultaneously printing as many divided sections as possible so long as the total number of heating registers to be powered simultaneously does not exceed a predetermined value and by printing one line (or printing unit) of a predetermined length. However, the system is disadvantageous in that it uses a stepping motor, or the like, as a paper feeding motor acting as paper feeding means for moving a paper at a limited velocity, because the vertical scanning velocity (i.e., the paper feeding velocity) must be abruptly decelerated or accelerated in a minimum amount of time. As is disclosed in Japanese Patent Laid-Open No. 58-205372, moreover, the prior art apparatus is caused to select smooth acceleration or deceleration (or a uniform rate of the vertical scanning velocity) according to the number of bits stored in a code buffer memory and the number of bits of image signals stored in a line memory. However, no consideration is given to fluctuations of the printing time period of each line (or Printing Unit). In case the image signals are coded by MH (i.e., Modified Huffman) codes or the international standard codes of facsimile, code and line buffers are required to have large capacities with complicated controls so that they may neither overflow nor underflow, because the transmission time period of each line fluctuates about several hundred times according to the content of the image signals.